Experimental verification of Faradaic charging in ac electrokinetics

This paper investigates the phenomenon of Faradaic charging in ac electrokinetics. Faradaic reactions were suggested as a key effect responsible for the reversal of pumping direction in ac micropumps. However, this hypothesis has yet to be proven convincingly and directly. Here we present an ion detection strategy to determine the production of ions through Faradaic hydrolytic reactions originating from direct application of voltage to electrolytic solutions during ac electrokinetics. Experiments were performed with symmetrical planar electrodes aligned along a microfluidic channel. Fluorescein, a pH-dependent dye, was employed as the pH indicator for the detection of ion production. Images were captured for analysis at various voltage levels. From analyzing the fluorescence intensity and its distribution, it can be concluded that the production of ions from hydrolytic reactions takes place and increases with the ac voltage. The coefficient of deviation indicates a significant enhancement at ac voltage above 11 V_pp. Lastly, we demonstrate a strategy using dc-biased ac electrokinetics to achieve controllability in direction and magnitude of the net fluid flow in pumping application.     

Los aspectos socioculturales del área de lengua extranjera y el programa linguapax

La enseñanza de lenguas extranjeras está experimentando un «enriquecimiento curricular» muy positivo. De considerarse como un simple instrumento vehicular de conocimientos o comunicación, las lenguas extranjeras están pasando a conectarse con el gran problema social y cultural de conocer otros pueblos, de conocer el mundo. El objetivo-medio de la globalización (con ciencias sociales principalmente pero no sólo) se convierte así en uno de los puntos fuertes de la enseñanza de otras lenguas.     

从巴厘岛到哥本哈根的崎岖道路

《京都议定书》是解决气候问题踏出的重要第一步,但2012年第一执行期结束后的后续国际协议还未能确定。要避免气候问题日益严重,2009年哥本哈根缔约方大会相当关键,各国政府必须达成一个能够持续并加深应对气候变化努力的协议,也就是《京都议定书》的后续方案。     

Análisis crítico del entorno,elección de alternativas y clarificación de valores

En el presente artículo se relacionan el conjunto de estrategias conocidas bajo el epígrafe de «clarificación de valores» con el desarrollo de la personalidad moral. Se especifican las fases a tener en cuenta en su puesta en práctica, ejemplificándose en actividades dirigidas en especial a los alumnos del tercer ciclo de la Educación Primaria, ofreciéndose prototipos de actividades para otros tramos educativos.     

Museum without walls： Imagining new formative spaces

The ＂Museum of Childhood＂ is a project connected to the Post-Graduate Program in Education at Unesc （Brazil） and since 2005 has been developing interfaces with research, teaching and extension. In this paper, the authors would like to show how the museological conception of the Museum of Childhood makes imagination from one of the central axis of its formative relation with the public. Such conception breaks with the traditional view of museums as buildings where old things are collected and preserved. In fact, the Museum of Childhood, in the light of its objective conditions, wants to be a museum without walls, a museum that, using the device of spatial demarcation, spreads itself in the university campus and other public places, with the objective of communicating with the people. This conception comes closer to the transgressive nature of modem arts, which desacralizes the work of art as masterpiece and proposed, for example, the fugacity of installations and aesthetic interventions. This conception takes the Benjaminian notion of the past as the dimension where other futures remain latent, that is, the museum is seen not as a guardian of the past, but as an establishment that wants to use its collections to communicate with the public. The overrunning of the static physical space, for example, forces the public to recreate its horizon of expectations concerning what a museum show be. In order to accomplish its original objectives, the Museum of Childhood works intensively on the formation of the public by proposing monitored visits in which creative activities are developed and by improving its homepage.     

The relative roles of IQ and cognitive processes in reading disability

The purpose of the present study was to explore the relative roles of IQ and cognitive processes in reading performance. A sample of 443 Spanish children (264 male, 179 female) ranging in age from 7 to 13 years were classified into four groups according to IQ scores (<80, 80–90, 90–110, >110) and reading disabled (RD) and normally achieving readers (NR) were compared. The findings indicate that IQ scores were not related to the differences between children with RD and NR. We found that reading‐related cognitive deficits do differentiate between RD and NR children. Therefore, IQ scores do not make a significant contribution to our understanding of reading disability.     

Teacher education graduates’ entrance into the teaching profession: Development and test of a model

This study aims to advance insight into the relationship between teacher education and graduates’ intended and actual entrance into the teaching profession. Moreover, it indicates how this relationship varies between teacher training for primary education (i.e., programs for class teachers-to-be) and teacher training for secondary education (i.e., programs for subject teachers-to-be). A hypothetical model of graduates’ entrance into the teaching profession comprising empirically grounded variables was developed. Besides teacher education related variables, other factors (e.g., motivation and labour market) were included. Data for this study were collected based on a sample of 301 teacher education graduates. Logistic regression analysis shows that intention to enter teaching is a valid predictor of actual entrance. Path analysis was applied to test the hypothetical pattern of (inter)relationships between the variables. For graduates from teacher training for pre-school and primary education, the path model accounts for 33% of the variance in intention to enter teaching. For teacher training for secondary education the explained amount of variance is 44%. Results are largely consistent across the two types of teacher training showing a small, although statistically significant, contribution of teacher education above other antecedents of graduates’ intention to enter teaching.     

Influencing Work-Related Learning: The Role of Job Characteristics and Self-Directed Learning Orientation in Part-Time Vocational Education

Based on the Demand-Control-Support (DCS) model, the present paper aims to investigate the influence of job characteristics such as job demands, job control, social support at work and self-directed learning orientation on the work-related learning behaviour of workers. The present study was conducted in a centre for part-time vocational education in Flanders (Belgium). The students in the centre work for 3 days a week and attend school during the other two days. A questionnaire using scales adapted from validated instruments was used. Students were asked to complete the questionnaire with the job in mind they were doing at present. A total of 115 students from different sectors completed the questionnaire. It was assumed that high scores for self-directed learning orientation and high scores for the job characteristics job demands, job control and social support would be associated with more work-related learning behaviour. All scales had acceptable Cronbach alpha values. The results of the linear regression analyses indicated that only the self-directed learning orientation scale predicted the work-related learning behaviour to a significant extent.     

Spheroid-on-chip microfluidic technology for the evaluation of the impact of continuous flow on metastatic potential in cancer models in vitro

The majority of cancer deaths are linked to tumor spread, or metastasis, but 3D in vitro metastasis models relevant to the tumor microenvironment (including interstitial fluid flow) remain an area of unmet need. Microfluidics allows us to introduce controlled flow to an in vitro cancer model to better understand the relationship between flow and metastasis. Here, we report new hybrid spheroid-on-chip in vitro models for the impact of interstitial fluid flow on cancer spread. We designed a series of reusable glass microfluidic devices to contain one spheroid in a microwell under continuous perfusion culture. Spheroids derived from established cancer cell lines were perfused with complete media at a flow rate relevant to tumor interstitial fluid flow. Spheroid viability and migratory/invasive capabilities were maintained on-chip when compared to off-chip static conditions. Importantly, using flow conditions modeled in vitro, we are the first to report flow-induced secretion of pro-metastatic factors, in this case cytokines vascular endothelial growth factor and interleukin 6. In summary, we have developed a new, streamlined spheroid-on-chip in vitro model that represents a feasible in vitro alternative to conventional murine in vivo metastasis assays, including complex tumor environmental factors, such as interstitial fluid flow, extracellular matrices, and using 3D models to model nutrient and oxygen gradients. Our device, therefore, constitutes a robust alternative to in vivo early-metastasis models for determination of novel metastasis biomarkers as well as evaluation of therapeutically relevant molecular targets not possible in in vivo murine models.